Carbonaceous feedstock such as coal and petroleum can be used to produce solid carbon materials. For example, coking coal, coal tar and coal tar pitch are typically used to produce the metallurgical coke or other types of carbon materials for the iron and steel industry or to produce the electrodes for the aluminium industry. However, a number of problems exist with the above-mentioned production of carbon materials.
In particular, some currently used raw feedstock, such as coking coal, is non-renewable and depleting. Coking coal represents only a small portion of available coal reserves. Unfortunately, other coals of lower or higher ranks than the coking coal, e.g. lignite, brown coal, sub-bituminous coal, low-caking bituminous coals and anthracite, do not possess the required caking properties to be suitable feedstock for making metallurgical coke.
Furthermore, the use of the carbon materials in the way described above leads to a significant emission of CO2 and other pollutants such as SO2 and NOx. In addition to the high sulphur content in the metallurgical coke produced from coking coal or petroleum, the ash yield is also relatively high, which creates many issues in their application in metallurgical industry.
In addition to the metallurgical industry, solid carbon materials with high strength are also required in other industries, e.g. wastewater treatment and gold mining and extraction. The solid carbon materials (e.g. activated carbon) must have good mechanic strength for use in these operations.
Biomass is the only renewable resource that can be directly used to make solid carbon materials. However, biomass-derived carbon materials are usually of insufficient quality to be a replacement for solid carbon materials such as metallurgical coke and high-strength activated carbon.
There is a need for high quality solid carbon materials produced from biomass or other relatively inexpensive low-caking carbonaceous feedstock.